In P-persistent CSMA network there are 5 systems in a slot. The probability of station not transmitting the data is 0.6. Only two stations should transmit the data to avoid collision. What is the probability that channel is collision free?
My answer is 0.6825 and answer given is 0.34 - 0.35.
I solved this as P (no collision) = either 2 stations are transmitting or 1 station or none.
In question ask only two stations transmit. So, we consider two stations only.
probability =5C2(0.42)(0.63)=0.3456